Gradometer.



No. 685,569. Patented Oct. 29, l90l.

, J. H. BULLABD.

GBADUMETER.

(Application filed Kay 21. 1901.)

(-No Model.)

PATENT OFFICE JAMES H. BULLARD, OF SPRINGFIELD, MASSACHUSETTS, ASSIGNOR TO,

OVERMAN AUTOMOBILE COMPANY, OF CHICOPEE,

MASSACI-IUSETT A CORPORATION OF MASSACHUSETTS.

G RADOMETER.

SPECIFICATION-forming part of Letters Patent N0. 685,569, dated October 29, 190i.

Application filed May 21,1901. Serial No. 61,286- (No model);

To all whom, it may cancer-n? Be it known that I, JAMES H. BULLARD, a citizen of the United States of America, residing at Springfield, in the county of Hampden and State of Massachusetts, have invented new and useful Improvements in Gradometers, of which the following is a specification.

This invention relates to gradometers, and has for its object the construction of an instrument'of this class adapted especially to use on self-propelled vehicles. I

It is well known that the bodies of motorvehicles when in motion are subject to strong and rapid vibration, due in part to the action of their propelling mechanism and in part to the use thereon for obvious reasons of wheels having relativelysmall diameters. The lightness of the construction of these vehicles also somewhat enhances these vibrations. The application of a gradometer as ordinarily constructed to one of these vehicles is practically useless, for the indicating-bubble under the eifects of the vibratory movements of the vehicles is so unsteady as to render its reading both difficult and unreliable. By means of this invention the indicating member is restrained in its movements and the reading of the gradometer may be quicklyi'and accurately made at all times, regardless of the condition of the road or speed of the vehicle.

In the drawings forming part of this specification, Figure 1 is aplan view of agradometor embodying my invention, and Fig. 2 is a side elevation of the same, partly in section, taken on line 2 2, Fig. 1.

Fig. -3 is a crosssection of Fig. 1 on line 3 3.

In carrying out my invention I make use of the usual curved glass tube a, mounted in a metal frame I), and starting from its center, which is its lowest point, is provided with graduation-marks 0, indicating the per cent. of inclination of the device relative to the horizon when the indicating member (1 rests on one of said marks. The tube a is filled with some non-freezing liquid, such as alcohol, and the indicating member d, consis ting of a metal ball, is inserted therein and the ends of the tube then sealed in any convenient way. If it is desired that the movements of the member din the tube shall take place against a considerable resistance, said member is made of such diameter as to almost fill the bore of thetube, and the liquid medium in which it moves may be, if desired, thickened with some .substance. like glycerin.

When constructed as above described, it is apparent that as the device is inclined from the horizontal the member 01 will by gravity seek the lowest point in the tube a; but it can only move in said tube as fast as permitted by the passageof a portion of the liquid on one side of it to the other side through the space left between the periphery of the member d and the bore of the tube. If that space is of small area, the member (1 will travel more slowly from point to point in the tube than if it were larger, and it is thus possible to so control the movements of the indicating member that it will not move with every vibration to which the vehicle-body on which it is supported is subjected.

To secure the tube a in the framebflprefor to construct the latter, as shown, in the form of a boxhaving an opening e in the upper side thereof of less width than the external diameter of the tube and a little shorter than the length of the latter and inverting the frame place thetube therein with its ends resting on the frame, as shown in Fig. 1, thenv filling in the interior of the latter with plaster-of-paris or other suitabletcement, (indicated by f.) The frame may then be secured to the vehicle-body in any position within sight of the operator of the vehicle.

To insure the proper operation of the device, it is obvious that the indicating member d must be of a specific gravity relatively great as compared with the medium in which itis immersed and must be of a true spherical shape, and I find thata steel ball moving in amedium of pure alcohol gives the most satisfactory results.

Having thus described my invention, what that of the bore of the tube, whereby the I claim,'and desire to secure by Letters Patmovements of the ball therein may be con- 10 en}; of thedUnited States, is-- ed trolled, substantially as described.

n agra omet'er aglass tube form on t e arc of a circle, a nd having sealed ends, a JAMES BUILARD' transparent liquid filling'said tube, gradua- Witnesses:

' tion-marks on the latter, and a metal ball in WM. H. CHAPIN,

' the tube,whose diameter closely approximates K. I. CLEMONS. 

